Lubricating composition



and scoring of the bearing surfaces takes Patented June 17, 1947 LUBRICATING COMPOSITION Amos T. Knutson and Eldon F. Graves, Midland, Mich, assignors to The Lubri-Zol Corporation, Wickliife, Ohio, a corporation of Ohio No Drawing. Application January 27, 1944, Serial No. 519,912

4 Claims. (Cl. 25 2-48.2)

This application is a continuation in part of our copending application Serial No. 14,295 filed April 2, 1935', now Patent No. 2,340,331 dated Feb.

This invention relates as indicated to lubrication and more particularly to the provision of a lubricating composition capable of withstanding greater pressure per unit area before seizure place than such pressures as a pure mineral oil may, for example, withstand.

It is a more particular object of this invention to provide a lubricating composition which is of such nature that it will react with the bearing surfaces in such manner as to be particularly effective for use under conditions resulting in thin film lubrication which maintain when the pressure between the bearing surfaces is in the neighborhood of or in excess of approximately 10,000 pounds per square inch.

It is a further object of this invention to provide a lubricating composition and a method of improving the lubricating properties of a lubricating Oil such as pure mineraloil particularly to increase the break-down pressure of the film of such oil between bearing surfaces, and consequently to improve the thin film lubricating characteristics of the oil.

The lubricating compositions of our inventions will be found to possess additional desirable properties hereinafter more particularly pointed out.

Other. objects of the invention will appear as the description proceeds.

Our invention, then, consists of the steps hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain steps embodying the invention, such disclosed steps constituting, however, but one Of the various ways in which the principle of the invention may be used.

The present invention contemplates the provision of a lubricating composition which contains certain organic derivatives of inorganic oxy-acids, such compounds being used with or without being admixed with a suitable oil base such as a mineral oil.

Where the lubricating composition in accordance with the present invention comprises such admixture, the components thereof may, as previously indicated, be broadly classified as the "oil base the organic derivatives of inorganic oxy-acids referred to for convenience as the addition agent.

The oil base The suitable oil base comprising one of the the present invention may be any suitable lubricating oil such as a mineral or vegetable oil or any suitable oil usable for purposes of lubrication. Furthermore, this invention contemplates 5 the use as lubricating oil base of Oils generally which may have been subjected to a particular treatment for the purpose of imparting thereto characteristics not originally possessed thereby and which render the same particularly suitable or in any event do not render them harmful for use as lubricants.

Addition agent The so-called addition agents, as previously explained, which are contemplated for use in lubricating compositions made in accordance with thepresent invention, may be broadly classified as certain organic derivatives of inorganic oxyacids.

20 Morespecifically this invention contemplates the use for the stated purposes of certain organic derivatives of sulphurous acid, and particularly those represented by the formula:

Where R is any organic radicle, and

R is selected from the class consisting of hydrogen, organic radicles, and basic radicles. Examples of R are the following:

Phenyl Methyl-phenyl Ethyl-phenyI Examples of R are the following:

(1) Organic radicles:

Where R" is an organic radicle, e. g. ethyl, phenyl (b) Inorganic, e. g.

Ammonium Sodium Potassium.

It will be noted that this class of compounds comprises the organic sulphinic acids and the esters and salts of such acids.

Inasmuch as lubricating oils may on occasion be subjected to elevated temperatures the more 7 3 stable of such compounds are preferred. It will be found that such compounds of the class enumerated as having a boiling point of over 140 C. or at most 170 C. will be best suited for the purpose in contemplation for the reason that they will not be volatilized and lost from the composition should the same in use, for example, be subjected to an elevated temperature. For certain uses, however, where elevated temperatures are not encountered, compositions having a lower boiling point than those above indicated will be found satisfactory.

Since the above identified broad class of addition agents contemplated for use by this invention includes the organic sulphinic acids and esters and salts of them, it becomes convenient to first refer to the sulphinic acids themselves. The following is a list of the most commonly known sulphinic acids which-may be used:

Benzene sulphinic acid Alpha-toluene sulphinic acid Naphthalene sulphinic acid Para-ethyl benzene sulphinic acid The halogen bearing derivatives of each of the above may also be used, for example:

Ethyl chlorbenzene sulphinic acid Chlor toluene sulphinic acid The esters of sulphinic acids usable as addition agents may be classified as follows, with an indication under each class of the esterifying agents which may be used in the preparation of them:

1. Alkyl esters, for example those derived from:

Methyl alcohol Ethyl alcohol 2. Aryl esters, for example those derived from:

, Phenol Chlorphenol Cresol Since it is within the contemplation of our invention to use the halogen bearing derivatives of the broad class of compounds referred to above, the following is a classification of such halogen bearing esters, with reference to the nature of attachment of the halogen atom:

The salts of sulphinic acids which may be used as addition agents may be derived from any organic or inorganic base such as the following:

Organic bases I Ethyl amine Tri-ethyl amine Aniline Di-ethyl aniline Inorganic bases The following are examples of salts prepared from'representative examples of sulphinic acids and bases given above:

It will be observed that the foregoing salts are derived from aliphatic substituted aromatic sulphinic acids. If desired, halogen may be included in the molecule when the salt is used, as by having a halogen, such as chlorine, attached to either the basic radicle or to the sulphinic acid radicle.

The exact mechanism by which addition agents, contemplated for use by the present invention, are effective in increasing the film strength of lubricants is not clearly understood, but it hasbeen suggested that certain elements, or groups of elements, may react with the metal atoms of the bearing surfaces, due to the stress of the rubbing action under severe conditions. The metal-bearing compounds so produced may then act to prevent actual contact of the metal surfaces, and may thus exert an anti-fluxing" action capable of inhibiting the welding together of a part of one surface with a part of the other.

It is assumed that scoring usually results from the tearing apart of such welded portions of the two surfaces.

The compounds contemplated by this invention as addition agents contain acid radicles,,or acidforming groups and are, therefore, capable of reacting with metals to form such anti-fluxing materials under the conditions assumed by the theory above described.

Certain addition agents seem to be capable of improving the lubricating qualities of a lubricant in another way, that is by increasing the oiliness of the lubricant, or its ability to reduce friction. These materials appear to have in common the tendency to be strongly adsorbed by metal surfaces. Such a tendency is characteristic of oxygen-bearing compounds in general, and particularly those which are of an acid, or acid-forming'character. It would, therefore, appear that the addition agents of this invention are particularly The halogen-bearing compounds of the type contemplated are particularly effective because of the presence of two separate means which may act to produce anti-fluxing materials, viz: the halogen, and the acid group. In addition, the presence of oxygen in the acid group, because of its tendency to be strongly adsorbed on metal surfaces, increases the effective concentration of the active ingredients at the bearing surfaces where they may function as requiredf Range of compositions suitable oil base.

For ordinary types of lubrication such as in the crankcase of internal combustion engines, it has been found that the two considerations which determine the amount of the addition agents which is to be added to a lubricating oil are,

well adapted for this purpose.

first, the cost of the resultant composition, and,

th extreme pressure characteristics of lubricating oils. Certain of the more active compounds may be entirely efiective for ordinary purposes when present in the amounts as low as fractions of 1% for example one-fourth and even as low as one-tenth percent.

Uses and advantages In addition to the advantages attained by the use of certain products contemplated by this invention to increase the film strength of lubricating oils or as lubricants possessing high film strength, other advantages may be obtained as follows. The compounds are in general relatively stable and therefore resistant to the composition oxidizing and to gum forming and sludge forming reactions, especially when used as crankcase lubricant in internal combustion engines. Certain of the compounds named are effective when present in mineral lubricating oil compositions to reduce the rate of change of viscosity with the temperature and usually have a tendency to prevent precipitation of crystalline or gelatinous materials, such as waxes, on chilling. Lubricants resulting from the use, either pure or mixed with other lubricating oils, of such products, therefore have the advantage of improving viscosity index and lowering pour point.

Of the various halogens which are available for use, chlorine is generally preferred, particularly due to the lower cost and greater availability of chlorine as compared to the other halogens. Certain of the other halogens such as fluorine and bromine, for example, do act slightly differently from chlorine but it has been found that any advantage in the use of other halogens over chlorine is generally not compensated for by the increased cost. 1

As previously indicated, the lubricating compositions made in accordance with the present invention are particularly applicable for use generally under high temperature and extreme pressure conditions.

It has been found that certain of the compounds above described either alone or in combination with other materials such as lubricating oils are capable of reducing the rate of wear of the bearing surfaces, particularly during thin film" lubrication, and especially when one of the bearing surfaces is of a so-called bearing metal type such as babbitt, brass and bronze.

I Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

1. A lubricating composition comprising a major proportion of mineral lubricating oil and an amount suificient to impart extreme pressure properties of p-ethyl benzene sulphinic acid.

2. A lubricating composition comprising a major proportion of mineral lubricating oil andan amount sufiicient to impart extreme pressure properties of a compound represented by the where R. is an aliphatic substituted aromatic radicle, and R is selected from the class consisting of hydrogen, organic radicles, and basic radicles.

3. A lubricating composition comprising a ma- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,346,155 Dennison et al Apr. 11, 1944 2,340,331 Knutson et al. Feb. 1, 1944 2,257,750 Lincoln et al. Oct. 7, 1941 2,204,620 Prutton et al. June 18, 1940 2,344,566 Lincoln Nov. 16, 1943 

